As foreclosures turn former homeowners into renters and new buyers stay on the sidelines, the apartment sector relishes its nascent recovery. Increased demand begat higher occupancy rates and rents, as well as new construction despite lingering headwinds from a sluggish economy. Homeownership — long considered the quintessential American dream — is at a 13-year low, but apartment growth, which was also hurt with the economic downturn, is seeing a comeback of sorts.